I have never seen a IDE/SATA converter. I have seen an external USB device that can plug into IDE or SATA laptop HDD (it mighta had desktop SATA, but I don't think it had desktop IDE). I would suggest getting an external enclosure for your new SATA HDD (external enclosures use USB usually).
Some of the newest motherboards have only 1 IDE drive, or none at all, relying on SATA instead. Not only is the narrower ribbon much easier to deal with in a case, but it's generally a better connection too (because of having several wires in parallel, which create a small electromagnetic field when current flows through them, bits passed through IDE have to go through at least triple-checking every single bit).